摘要:
The action of palladium acetate on the Schiff bases 4-ClC6H,CH=N-CH(R-2)COOR1 (R-1 = Me, Et; R-2 = Ph, CH2Ph), in acetic acid for 3 h at 70 degreesC and subsequent treatment of the reaction residues with LiCl in acetone, affords the corresponding chlorobridged five-membered endo-metallacycles [PdCl(C-N)](2), 1a, 2a. The action of palladium acetate on the Schiff bases 2,6-Cl2C6H,CH=N-CH(R-2)COOR1 (R-1 = Me, Et; R-2 = Ph, CH2Ph), in chloroform at room temperature and subsequent treatment of the reaction residues with LiCl in acetone, affords the corresponding chloro-bridged five- or six-membered exo-metallacycles, by metallation of the amino acid moiety [PdCl(C-N)](2), 3a-exo, 4a-exo. A small amount of the endo-metallacycles was also obtained, probably by oxidative addition of the ortho C-Cl bond of these immes to Pd(0) formed in situ. Reaction of dimers 1a-4a with PPh3 affords the mononuclear complexes [PdCl(C-N)(PPh3)] 1b-4b. (C) 2002 Elsevier Science B.V. All rights reserved.